document nginx config changes

example.nginx.conf

@@ -32,7 +32,7 @@ server {
     set $scriptSrc  "'self'";
     set $connectSrc "'self' wss://cryptpad.fr wss://api.cryptpad.fr";
     set $fontSrc    "'self'";
-    set $imgSrc     "data: *";
+    set $imgSrc     "data: * blob:";
     set $frameSrc   "'self' beta.cryptpad.fr";
 
     if ($uri = /pad/inner.html) {
@@ -65,8 +65,12 @@ server {
         rewrite ^.*$ /customize/api/config break;
     }
 
+    location ^~ /blob/ {
+        try_files $uri =404;
+    }
+
     ## TODO fix in the code so that we don't need this
-    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard)$ {
+    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard|file|media)$ {
         rewrite ^(.*)$ $1/ redirect;
     }